From The NYC forecast office of the National Weather Service: this radar loop from dawn, Aug. 22, 2014, which shows a vast gathering of tree swallows taking off from the Connecticut River. "They're likely Tree Swallows that roost on islands on the river every night around this time of year." Via Facebook , and Andrew Revkin/NYT.

http://feeds.boingboing.net/~r/boingboing/iBag/~3/qb9fgLR64g8/a-torrent-of-tree-swallows-ca.html